Herbicidal method and compositions

ABSTRACT

WHEREIN R1 is hydrogen or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano, and lower alkoxy; R2 is R1 or a lower alkoxy radical, except that R1 and R2 cannot both be hydrogen; R3 is hydrogen or a lower alkyl radical; R4 is hydrogen, a lower alkyl radical, or a lower cycloalkyl radical; and R5 is hydrogen, a lower cycloalkyl radical, a lower alkoxy radical or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano, or lower alkoxy, except that R4 and R5 cannot both be hydrogen or a lower cycloalkyl radical.   Unwanted plants are controlled by applying a phytotoxic amount of a thiadiazole compound having the general structure:

[ HERBICIDAL METHOD AND COMPOSITIONS [75] Inventor: Tony Cebalo, Indianapolis, Ind.

[73] Assignee: Air Products and Chemicals, Inc.,

Allentown, Pa,

22 Filed: Jan. 22, 1973 21 Appl. No.: 325,485

Related US. Application Data [63] Continuation-in-part of Ser. No. 77,719, Oct. 2, 1970, Pat, No. 3,726,892, which is. a continuation-in-part of Ser. No. 867,385, Oct. 17, 1969, abandoned.

[52] US. Cl. 71/90 [51] Int. Cl AOln 9/12 [58] Field of Search ..L 71/90 [56] References Cited UNITED STATES PATENTS 3,657,264 4/1972 Rucker et alv 7l/90 3,658,830 4/1972 Pilgram 7l/90 Primary Examinerlames 0. Thomas, Jr. Attorney, Agent, or FirmLeroy Whitaker Dec. 24, 1974 [57] ABSTRACT Unwanted plants are controlled by applying a phytotoxic amount ofa thiadiazole compound having the general structure:

| R1R2NSO2 NCONR4R5 wherein 5 R is hydrogen or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano, and lower alkoxy;

R is R, or a lower alkoxy radical, except that R and R cannot both be hydrogen;

R is hydrogen or a lower alkyl radical;

R is hydrogen, a lower alkyl radical, or a lower cycloalkyl radical; and

R is hydrogen, a lower cycloalkyl radical, a lower alkoxy radical or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano, or lower alkoxy, except that R, and R cannot both be hydrogen or a lower cycloalkyl radical.

10 Claims, N0 Drawings 1 HERBICIDAL METHOD AND COMPOSITIONS CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of my copending application Ser. No. 77,719, filed Oct. 2, 1970, now US. Pat. No. 3,726,892 which in turn is a continuation-in-part of then copending application Ser. No. 867,385, filed Oct. 17, 1969, now abandoned.

BACKGROUND OF THE INVENTION compounds shown in the prior art such as, for example,

1-( S-methyll ,3,4-thiadiazol-2-yl )-3-phenylthiourea and 1-(5 -methyll ,3,4-thiadiazol-2-yl)-3-phenylurea [J. Pharm. Soc. Japan 74, 1044-8 (1054); CA 11630] were not reported to have biological activity. Compounds similar to the present invention are also disclosed in Belgian Patent 721,034.

An article in Farmaco Ed. Sci. 22 (6), 393-401 (1967) discloses the use of l-(5-alkyl-1,3,4thiadiazol- 2-yl)ureas as intermediates for the production of isomeric 1,3-bis-(5-alkyl1,3,4-thiadiazol-2-yl)ureas which latter compounds are alleged to exhibit hypoglycemic action. These compounds are only generally related to those employed in the instant invention.

It is known to control vegetation by the use of phytotoxic chemicals. Many such phytotoxic chemicals have been disclosed in the prior art. Certain herbicidal thiadiazolylureas are described, for example, in South African Pat. No. 69/1559, published Sept. 22, 1969. It is not believed that compounds of the type disclosed herein have been used previously in the control of vegetation.

SUMMARY Unwanted plants are controlled by applying to such vegetation or the seeds thereof a phytotoxic amount of a compound having the formula wherein R, is hydrogen or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano and lower alkoxy;

R is hydrogen, a lower alkoxy radical, or a substituted or unsubstituted lower alkyl radical, the sub stituents being selected from the class consisting of halo, hydroxy, cyano and lower alkoxy, provided that R, and R cannot both be hydrogen;

R is hydrogen or a lower alkyl radical;

R is hydrogen, a lower alkyl radical or a lower cycloalkyl radical; and

R is hydrogen, a lower cycloalkyl radical, a lower alkoxy radical, or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano, or. lower alkoxy, provided that R, and R cannot both be hydrogen or a lower cycloalkyl radical;

and tautomers thereof wherein R is hydrogen.

Novel herbicidal compositions comprising a compound of the above formula and an inert diluent are also claimed.

DESCRIPTION OF THE PREFERRED EMBODIMENT N N-H a n nso i i:ncoNR.,R

Generally, the compounds of the present invention may be prepared by one or more of the synthesis routes set forth below. The type of product desired will determine the particular synthesis routed to be employed.

HN N

a cit coclv I II s NCOCH3 (or) CH COOH s II-----N I L III (3150;, NCOCI-I l mama N N I VII l i IV c1so,,- NCONB R R R NSO i---r rc:ocrr

RIRQNH H01 N n N n.

2' R3 v VIII -NCONR R R R NSO NHR R RzNsoa a s 1 a 2 \S/ s .N N N N l; l R3 I (1) rcorr J I I IRIRBNSOQ I rrcomga R1R2NS02 --NCONRXRS s s I (11) 33X Neon/1,, i N v 3 I I ll 1 I 1 mm I NCON'R4R5 s 3 S XIV Generally, the compounds corresponding to formula (I) are known; however, others are prepared by standard methods. The S-acetamido-l,3,4-thiadiazoles (II) utilized are prepared by known methods from (I) and the corresponding sulfonyl chlorides (III) are also prepared by known methods. A particularly useful method is that of Petrow et al. (J. Chem. Soc. 1508, 1958). The sulfonamides (IV) are prepared by the reaction of the sulfonyl chlorides with primary or secondary amines in aqueous or nonaqueous solutions at temperatures of 0-60 C., preferably in the range 0l0 C. For nonaqueous reactions inert solvents such as benzene, halogenated hydrocarbons, tetrahydrofuran and the like can be used. The 2-amino-5-sulfonamido-l ,3,4- thiadiazoles (V) are obtained by the treatment of compounds (IV) with concentrated hydrochloric acid according to the method of Petrow et al. (loc. cit.).

A number of Z-ureido-l ,3,4-thiadiazole sulfonyl chlorides (VII) and 2-ureido-l ,3,4-thiadiazole sulfonamides (VIII) are prepared by methods similar to those employed to produce compounds (III) and (IV).

Other ureido compounds may be derived from compound (V) according to a variety of methods which are used for the preparation of such compounds and which are well documented in the chemical literature. For example, compounds of structure (V) may be reacted with isocyanates in an inert solvent such as benzene, dimethylformamide, ethyl acetate and the like. A catalyst such as triethylamine may be employed for this reaction.

VII

II i

6 A further reaction which may be employed is that in The following examples are illustrative of the invenwhich N,N carbonyldiimidazole is reacted with an tion and are not intended to limitthe scope thereof. aminothiadiazole to give an intermediate isocyanate which is then further reacted with an amine to produce 5 SYNTHESIS OF INTERMEDIATES the desired product.

N N N N N N N N N I R3R4NH i R R NSO F-- RIRZNSOE s S Phosgene may also be reacted with an amine to give i EXAMPLE 1 a carbamoyl chloride which is then further reacted with To a well stirred mixture containing 231 gms. of polya primary or secondary amine to produce the desired phosphoric acid and 488 gms. of acetic acid and heated urea product. This reaction may be carried out in the to 100 C. was added 300 gms. of 2-amino-5-mercaptopresence of a base, e.g., tertiary amine, and/or a cata- 1,3,4-thiadiazole. Upon complete addition of the thialyst such as boron trifluoride-ether complex. These rediazole, the mixture was stirred for an additional one actions can also be carried out in inert solvents such as hour at 120 C. The mixture'was cooled to C. and aromatic hydrocarbons, dimethyl formamide, tetrahypoured into ice water to provide a solid residue which drofuran and the like. was subsequently separated by filtering. The residue N N N N I l i R R NS 0, NHR 0001 R R NSO NCOCl l R R NH a a irso L 'i NCONR4R5 s The ureas of the invention which correspond to the was dissolved in 10 percent sodium hydroxide (the generic formula (lX) will form metal or ammonium i small amount of insolubles being removed by filtering) salts (substituted or unsubstituted) corresponding to and the solution being adjusted to a pH of one with 6N structure (X). For p'olyvalent metals, -these salts are hydrochloric acid. The solid product was identified to chelate in character. The alkali metal and ammonium be 2-acetamido-5-mercapto-1,3,4-thiadiazole having a salts also possess the highly desirable property. for agri- 45 melting point of 293-294 C. cultural applications, of being water soluble. Furthermore, alkali metal salts are found to react with reactive EXAMPLE 2 halogen compounds, e.g., alkyl halides, to produce de- One hundred fifty grams of 2-ace=tamido-5-mercaptorivatives as shown in (X1) and (Xll) below. v l,3,4-thiadiazole was suspended in 3.5 litres of per- N N N N I I I r g n R1R3NSO3- S/ NHCONRRS RLRQNSOQ SI/""=NCONR4R5 IX X Y a metal or ammonium radical n equivalence of Y N---N PI Iii-Ra XI XII cent acetic acid and cooled to a temperature of -5 C. A stream of chlorine gas was slowly bubbled through the cooled mixture at the above temperature for about 2 hours with vigorous stirring. The solids were separated by filtering, washed with ice water and air dried. The solid product was identified to be 2-acetamido-5- chlorosulfonyl-l ,3,4-thiadiazole having a melting point of 237239 C.

EXAMPLE 3 Two hundred fifty milliliters of a 40 percent solution of aqueous dimethylamine was added to 168.5 gms. of 2-acetamido-5-chlorosulfonyll ,3 ,4-thiadiazole while maintaining the temperature below 20 C. After stirring the mixture for about 4 hours the mixture was acidified with 6N hydrochloric acid, the solids separated by filtration and washed thoroughly with water. The solid product was identified to be 2-acetamido-5-N,N- dimethylsulfonamido-l,3,4-thiadiazole having a melting point of 258-260C.

EXAMPLE 4 A mixture containing 181.6 gms. of 2-acetamid0- 1,3,4-thiadiazole-5-N,N-dimethylsulfonamide and 1000 mls. of concentrated hydrochloric acid was refluxed for about 3% hours. The mixture was cooled to room temperature, filtered and the filtrate concentrated to dryness under vacuum. The solid residue was admixed with 200 mls. of percent aqueous sodium carbonate and filtered. The resulting solid residue was identified tobe 2-amino-1 ,3,4-thiadiazole-5-N.N-dime' thylsulfonamidc and having a melting point of I84 l86 c.

EXAMPLE 5 A mixture containing 8.0 gms. of 2-amino-5-mercapto-1,3,4-thiadiazole, 3.4 gms. of methyl isocyanate and 150 mls. of N,N-dimethylformamide was heated to 50 C. for about one hour. The reaction mixture was concentrated under vacuum and ice water subsequently added tothe concentrate. The solid residue was separated by filtration and identified to be 1-methyl-3-(5- mercapto-1,3,4-thiadiazole-2-yl)urea having a melting point of 234C.

EXAMPLE 6 Sixty grams of 1-methyl-3-(5-mercapto-1,3,4- thiadiazol-2-yl)urea was suspended in 1.32 litres of 70 percent acetic acid, the mixture being formed in a flask equipped with a mechanical stirring means. The mixture was cooled to about 5 C. and chlorine gas slowly bubbled through for about 45 minutes while maintaining the 5 C. temperature. The resulting solids were separated by filtration, washed with water and air dried. The product was identified to be l-methyl-3-(5' chlorosulfonyl-1,3,4-thiadiazol-2-yl)urea melting point of 141 C.

SYNTHESIS OF FINAL PRODUCTS EXAMPLE 7 Twenty grams of 1-methyl-3-(S-chlorosulfonyl-l ,3,4- thiadiazo1-2-yl)urea was dissolved, with stirring, in 250 mls. of a 40 percent aqueous solution of methylamine while maintaining the temperature of the reaction from having a about 5-7 C. After stirring for an additional 1% hours, the mixture was acidified to pH 1 with 6N hydrowas chloric acid, the solids were separated by filtration and subsequently washed with water. The final product was identified to be 1'methy1 3-(S-N-methylsulfamoyl- 1,3,4-thiadiazol-2'yl)-urea having a melting point of 232233 C.

' EXAMPLE 8 A mixture containing 4.1.gms. of Lamina-1,3,4- thiadiazole-5-N,N-dimethy1sulfonamide and 1.3 gms. of methylisocyanate was refluxed in anhydrous benzene for 3 hours. The mixture was cooled to 10 C., the solid product was separated by filtration and subsequently crystallized from ethanol. The final product identified, to be 1-methyl-3-(5-N,N- dimethylsulfamoyl-l,3,4-thiadiazol-2-y1)urea having a melting point of 223235 C.

EXAMPLE 9 A mixture containing 18.0 gms. of 2-amino-1,3,4- thiadiazole-5-(N-methyl-N-butyl)sulfonamide, 5.4 gms. of methylisocyanate and 300 mls. of anhydrous dimethylformamide was heated to and maintained at 50 C. for about 1 hour. The dimethylformamide was removed under vacuum and the solid residue crystallized from solox. The final product was identified to be l-methyl-3-(5-N-butyl-N-methylsulfamoyl-1,3,4- thidiazol-2-yl)urea having a melting point of l92193 C.

EXAMPLE 10 The procedure of Example 9 was substantially repeated except that 13.8 gms. of 2-amino-l,3,4- thiadiazole-S-N-butyl sulfonamide, 4.3 gms. of methylisocyanate and 250 mls. of anhydrous dimethylformamide were employed. The final product was identified to be 1-methyl-(S-N-butylsulfamoyl-l,3,4- thiadiazol-2-yl)urea having a melting point of 186-187 C.

EXAMPLEll A mixture containing 28.2 gms. of 2-amino-1,3,4- thia-diazole-S-N,N-dimethylsulfonamide, 12.5 gms. cyclopropylisocyanate and 400 mls. of anhydrous dimethylformamide was heated to and maintained at 50 C. for about 1 hour. The dimethyl-formamide was removed under vacuum, leaving a solid residue which was crystallized from methanol. The final product was identified to be 1-cyc1opropyl-3-(5-N,N- dimethylsulfamoyl-1,3,4-thiadiazol-2-yl)urea having a melting point of 216 C.

EXAMPLE '12 EXAMPLE 13 To a mixture containing 100 mls. of methanol, and gms. 1-methyl-3-(5-N,N-dimethylsulfamoyl-1,3,4- thiadiazol-2-yl)-urea was added 2.4 gms. of potassium hydroxide and 5.4. gms. of methyl iodide, the entire mixture being refluxed for 30 minutes. The solids were separated by filtration and the filtrate concentrated under vacuum to provide a solid residue. The residue was recrystallized from methanol. The final product was identified to be 1,3-dimethyl-3-(5-N.N- dimethylsulfamoyl-l,3,4-thiadiazol-2-yl)urea having a melting point of 209-212 C.

EXAMPLE 14 1 To a mixture of 6 gms. of N,N-carbonyldiimidazole in dry tetrahydrofuran, under an atmosphere of nitrogen, was added 3.5 gms. of 2-amino-1,3,4-thiadiazole- EXAMPLE 15 To a stirred suspension of 80 gms. of S-methylamino- 2-mercapto-1,3,4-thiadiazole in 300 mls. of methanol was added, in small portions, 26 gms. of sodium hydroxide. The stirring was continued until a complete solution was obtained (a small amount of insoluble material being removed by filtration). Iodine (66.4 gms.) dissolved in 350 mls. of methanol was next added dropwise to the above stirred solution. A yellow precipitate began to separate after approximately half of the iodine solution had been added. After complete addition of the iodine solution the solids were filtered off and washed with a little methanol to give the desired di-5- (methylamino-l.3.4-thiadiazolyl) disulfide (X111, R CH having a melting point of 202-204 C.

EXAMPLE 16 A mixture containing 4 gms. of di-5-(2-methylamino- 1,3,4-thiadiazolyl) disulfide, 1.6 gms. of methyl isocyanate, and 20 mls. of N,N-dimethylformamide was heated at 100C. for 1.75 hours. Water was next added to the reaction mixture until a precipitate appeared. The total solids which precipitated on further cooling were removed by filtration and were washed thoroughly with water. The resulting product was identified to be di-S-l1,3,4-dimethyl--3-(1,3.4-thiadiazol-2- yl)urea] disulfide (XlV, R H; R;, R CH;,) having a melting point of 219-221 C.

EXAMPLE 17 Four grams of di-S-l1,3-dimethyl-3-(1,3,4- thiadiazol-2-yl)urea] disulfide was suspended in 120 mls. of percent acetic acid, the mixture being formed in a flask with mechanical stirring means. The mixture was cooled to about 10 C. and chlorine gas slowly bubbled through for 1 hour while maintaining a temperature range of 10-15 C. After approximately 30 minutes the reaction mixture became clear. The reaction mixture was next diluted with water and extracted with chloroform. The chloroform solution was washed with water, dried (Naand concentrated under vacuum to give the desired 1,3-dimethyl-3-(5- chlorosulfonyl-1,3,4-thiadiazol-2-yl)urea having a melting point of 98-l00 C. (dec.).

EXAMPLE 18 To a stirred mixture containing 1.5 gms. of 1,3- dimethyl-3-( 5-chlorosulfonyll ,3,4-thiadiazol-2- yl)urea and 0.5 gms. of dimethylhydroxylamine hydrochloride in 20 mls. of tetrahydrofuran was added, dropwise, 1.0 gms. of triethylamine in 5 mls. of tetrahydrofuran and the reaction mixture stirred overnight at room temperature. The reaction mixture was next filtered and the filtrate concentrated under vacuum to a solid residue. This solid was dissolved in ethyl acetate,

Melting Example R, R R R R, Point. "C

19 C(CH l H H H CH 247-249 20 CH CH CH(OCH3)z H H CH 156-158 21 CICH CH H H H CH 197-199 22 CH CH;,O H H CH 167-169 23 CH CHCH OCH H H H CH 174-176 24 CH CN CH: CH; H CH 200-202 25 CH CN C,H H H CH 127-130 26 CH CH H H CH,CH=CH, 213-215 27 CH CH H CH CH 187-189 28 CH =CHCH H H H CH 166-168 29 a 1 C H H H CH 158-159 30 ClCH CH CICH CH CH H CH 176-178 31 CH CH H H ClCH CH 198-200 32 CH CH CH CH H CH 152-154 33 CH; ClCH CH CH CH H CH -107 34 CH CH CH CH CH CH 68-70 35 CH CH N'Na H CH; 234-236 36 CH CH CH(OCH CH H CH 149-151 37 C(CH H CH v H CH 210-212 38 H CH CICH CH, H H Ch 164-166 39 CH CH H CH CH CH(OCH )z 142-144 12 Continued Meltin hxamplc 1. 2 3 R4 R Point. C

40 CH CH CH CH CH oil 41 CH CH H H CH CHCH OCH 162-164 42 CH CH H H C(CH C CH 202-204 43 di(CH CH(OCH CH;) CH H CH 101-102 44 CH; ClCH CH CH CH CH oil .45 H CH;CH(OCH3)2 CH H CH 128-130 46 H CHQCHCHQOCH] CH H CH 167-169 47 CHgCHg ClCH CH CH H CH 155-157 48 CH; CH CH(OCH CH CH CH 78-79 49 CH; CH 3 NK H CH 213-215 50 CH CH NK H CH CH%H 214-216 d. 51 CH;, OCH H CH OCH 133-135 52 CH;, OCH CH CH CH 125-128 53 CH CH CN CH CH CH 95-97 54 CH CH H CH CH CHCH CH; 178-180. 55 CH;, ClCH CH CH H CH 151-153 56 H ClCH CH CH H CH 151-153 57 CH;, CH CHCH CH CH H CH 149-151 58 CH CH CHCH CH CH CH CH 60-62 59 CH CH CH H CH 138-140 OCH Salt formed at R: position.

Biological Activity of Final Products The herbicidal activity of products of the invention was tested in accordance with the procedure hereinafter set forth. For preemergence testing the soil in which seeds were planted was sprayed the same day with a solution containing the designated amount of product in a 50-100 percent acetone-water mixture. Observations of activity were recorded 21 to 28 days after planting and spraying. For postemergence testing the plants were sprayed with the same solution as described above about 14 days after planting of the seeds. A kill rating was adopted to assess the phytotoxicant properties of the products. For both testing procedures a percent kill rating for each species of plants was obtained by comparing the stand of treated plantings with untreated control plants growing under similar conditions.

The results of this test are reported in Tables 1 and 11. The results under each plant species are expressed in terms of percent killed.

In a second series of tests, the plant species to be used as indicators of herbicidal activity were planted in galvanized pans (flats) which were 31.5 cm. long, 21.5 cm. wide and 8 cm. deep. The soil used was a one to one mixture by volume of masonry sand and shredded top soil. The flats were filled two-thirds full with soil and the soil was leveled and tamped. For preemergence testing, the seeds are planted in rows parallel to the long axis, one species per half row. For postemergence testing, the seeds are planted in rows perpendicular to the long axis of the flat, one species per row.

After planting, the seeds were covered with 0.5 to 1.0 cm. of screened, sterilized soil. Two and one-half grams of soluble fertilizer were applied to each flat during the initial watering. The preemergence flats were treated the same day they were planted. Postemergence flats were planted to 13 days prior to treatment and placed in a growth room until the day of treatment. In the growth room, flats received 12 to 18 hours of light each day and the temperature was maintained at 74-80 F. After treatment, both preemergence and postemergence flats were placed in a greenhouse.

Each test compound was dissolved in a one to one mixture of acetone and ethanol containing a small amount of Toximul R and S (a sulfonate/nonionic blend, Stepan Chemical Company, Northfield, lllinois).

The solution was then diluted to the appropriate volume with deionized water. The base solution was then rated against each plant species employed. Ratings are based on a 1 to 5 scale as follows:

1 no injury 2 slight injury 3 moderate injury 4 5 severe injury 5 death The results of this test are reported in Table 111. When more than one test was run at the same rate the numbers reported are averages.

In all of the tables that follow, the plant species used are identified by letters appearing across the top of the table. The legend for'use in identifying the plants is as.

follows:

A Corn (Zea mays) B Cotton (Gossypium hirsutum) C Soybean (Glycine max) D Wheat (Triticurn aesitivum) E Alfalfa (Medicago sativa) F Sugar Beet (Beta vulgaris) G Rice (Oryzasativa) H Cucumber (Cu'cumis sativus) J Tomato (Lycopersicon esculentum) K Barnyardgrass (Echinochloa crusgalli) L Cocklebur (Xanthium pensylvam'cum) M Large Crabgrass (Digitaria sanguinalis) N Mustard (Brassica sp.) 0 Pigweed (Amaramhus retroflexus) P Foxtail Millet (Setaria italica) Q Wild Oat (Avena fatua) R Velvetleaf (Abutilon theophrasti) S Morning Glory (lpomoea purpurea) T Zinnia (Zinnia elegans) U Clover (Malilorus indica) V Buckwheat (Fagopyrum tataricum) W .limsonweed (Datura srramom'um) TABLE 111 Continued Herbicidal Activity Postcmergent Prccmergent Rate.

Cpd.

N0./A ABCDEFGHJKLMNOPORST AMOPRST 3 4 2 3 4 4 2 3 3 3 1 2 H 2 H 3 4 2 l 2 3 1 4 2 3 1 3 1 2 1 1 2 1 3 1 2 2 2 1111 21 8 2 TABLE III -Continued Herbicidal Activity C d Rate ent Postemergent N0. NQJA ABCDEFGHJKLMNOPQRST AMOPRST When utilized for herbicidal purposes, compounds of the invention may be formulated in a variety of ways and concentrations for application to the locus of desired vegetation control. Such formulations comprise an inert diluent, liquid or solid, and at least one compound of this invention. It is recognized that the particular type and concentration of formulation, as well as the mode of application of the active ingredient, may govern its biological activity in a given application.

Compounds of the invention may be prepared as simple solutions of the active ingredient in an appropriate solvent in which it is completely soluble at the desired concentration. Such solvent systems include water, alcohols, acetone, aqueous alcohol and acetone, and other organic solvents. These simple solutions may be further modified by the addition of various surfactants, emulsifying or dispersing agents, colorants, odorants, antifoaming agents, other herbicides or herbicidal oils which supplement or synergize the activity of the herbicides of the invention, or other adjuvants for any given application where deemed desirable to impart a particular type or degree of plant responses.

Compounds of the invention may also be formulated in various types of formulations commonly recognized by those skilled in the art of agricultural or industrial chemicals. These formulations include, for example, compositions containing the active ingredient as granules of relatively large particle size, as powder dusts, as wettable powders, as emulsifiable concentrates or as a constituent part of any other known type of formulation commonly utilized by those skilled in the art. Such formulations include the adjuvants and carriers normally employed for facilitating the dispersion of active ingredients for agricultural and industrial applications of phytotoxicants. These formulations may contain as little as 0.25 percent or more than 95 percent by weight of the active ingredient.

Dust formulations are prepared by mixing the active ingredient with finely divided solids which act as dispersants and carriers for the phytotoxicant in applying earth, or other common organic or inorganic solids. Solids utilized in preparing dust formulations of the active ingredient normally have a particle size of 50 microns or less. The active ingredient of these dust formulations is present commonly fromm as little as 0.25 percent to as muchas 30 percent or more by weight of the composition.

'Granular formulations of the active ingredients are prepared by impregnating or adsorbing the toxicant on or into relatively coarse particles of inert solids such as sand, attapulgite clay, gypsum, corn cobs or other inorganic or organic solids. The active ingredient of these granular formulations is commonly present from 1.0 percent to as much as 20.0 percent or more by weight of the composition.

Wettable powderformulations are solid compositions of matter wherein the active ingredient is absorbed or adsorbed in or on a sorptive carrier such as finely divided clay, talc, gypsum, lime, wood flour, fullers earth, kieselguhr or the like. These formulations preferablyare made to contain 50 percent to 80 percent of active ingredient. These wettable powder formulations commonly contain a small amount of a wetting, dispersing or emulsifying agent to facilitate dispersion in water or other liquid carrier utilized to distribute the phytotoxicant to the locus of desired vegetation control.

Emulsifiable concentrate formulations are homogeneous liquid or paste. compositions containing the active ingredient which will disperse in water or other liquid carrier to facilitate applications of the phytotoxicant to the locus of desired vegetation control. Such emulsifiable concentrate formulations of the active ingredients may contain only the active ingredient with a liquid or solid emulsifying agent or may contain other relatively nonvolatile organic solvents such as isophrone, dioxane heavy aromatic naphthas, xylene, or dimethyl formamide. The active ingredient in such formulations commonly comprises 10.0 percent to 70.0 percent by weight of the phytotoxicant composition.

In place of the particular compositions employed to produce the products of the invention, other compositions and procedures may also be employed to produce products of the invention having substantially the same degree of biological activity.

The compounds described herein'can be used to control unwanted plants by either preemergent or postemergent application. However, the compounds are more active when applied postemergent and will probably find their greatest utility in postcmergent applications. The compounds show little selectively and should be considered to be active against virtually all plant species until suitable tests have shown a particular species to be tolerant.

As can be seen from the tables, some of the compounds exhibit a high degree of activity at rates as low as 0.05 pounds per acre. On the other hand, some of the less active compounds, such as numbers 9, 12, 26, 27, 30 and 31, may require pounds per acre to exhibit significant activity. Thus, depending upon the particular compound chosen, the plant to be destroyed and weather conditions, a herbicidally effective or phytotoxic amount of the present compounds might range from 0.05 to about 20 pounds per acre. The preferred range is from about 0.5 to about 4 pounds per acre.

The preferred compounds for use in the claimed method and compositions are those wherein R in the above formula is lower alkyl. Particularly preferred are l(5-dimethylsulfamoyll ,3,4-thiadiazol-2-yl l .33- trimethylurea, I-(S-dimethylsulfamoyl-l ,3 ,4- thiadiazol-2-yl)-1,3-dimethylurea, l-[ 5-( N-2- chloroethyl )-N ethylsulfamoyl l ,3 ,4-thiadiazol-2-yl 1,3-dimethylurea, l-[S-(N-cyanomethyl-N- methylsulfamoyl l ,3,4-thiadiazol-2-yl]- l ,3,3- trimethylurea, l-[5-(N-sec-butyl-N-methylsulfamoyl) 1,3,4-thiadiazol-2-yl1-l,3-dimethylurea and l-l5-(N- sec-butyl-N-methyl-sulfamoyl l ,3 ,4-thiadiazol-2-yl ll,3,3-trimethylurea I claim:

1. A method for the control of unwanted plants which comprises contacting such plants with a phytotoxic amount of a compound having the formula wherein R, is hydrogen or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano and lower alkoxy;

R is hydrogen,.a lower alkoxy radical, or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano and lower alkoxy, provided that R and R cannot both be hydrogen;

R is hydrogen or a lower alkyl radical;

R is hydrogen, a lower alkyl radical or a lower cycloalkyl radical; and r R is hydrogen, a lower cycloalkyl radical, a lower alkoxy radical, or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano, or lower alkoxy, provided that R, and R cannot both be hydrogen or a lower cycloalkyl radical;

and tautomers thereof wherein R is hydrogen.

2. A method as in claim 1 wherein R is lower alkyl.

3. A method as in claim 2 wherein the compound is l-(S-dimethylsulfamoyl-l ,3,4-thiadiazol-2-yl)-l ,3,3- trimethylurea.

4. A method as in claim 2 wherein the compound is l-(S-dimethylsulfamoyl-l ,3,4-thiadiazol-2-yl )-l ,3- dimethylurea.

5. A method as in claim 1 wherein the compound iss() R R N 2 4: 5 l 2 I S/ R 21 .22 wherein lower alkyl radical, the substituents being selected R is hydrogen or a substituted or unsubstituted lower from the class conslstlng of halo hydroxy' cyano alkyl radical, the substituents being selected from or lower alkoxy provided that 4 and R5 Fannot the class consisting of halo, hydroxy, cyano and both be hydrogen or rad'cal; lower alkoxyr 5 and tautomers thereof wherein R is hydrogen.

R is hydrogen, a lower alkoxy radical, or a substituted or unsubstituted lower alkyl radical, the substituents being selected from the class consisting of halo, hydroxy, cyano and lower alkoxy, provided 8. A composition as in claim 7 wherein the com pound is one wherein R is lower alkyl.

9. A composition as in claim 8 wherein the com pound is l-(5-dimethylsulfamoyl--1,3,4-thidiazol-2-yl)- that R, and R cannot both be hydrogen; l l33 trimethy|urea R is hydrogen or a lower alkyl radical; l0 l 8 h h R is hydrogen, alower alkyl radical ora lower cyclo- A .composmpn as m 0 mm w erem. t alkyl radical' and pound 1s l-(-dimethylsulfamoyl-l,3,4-thiad|azol-2- R is hydrogen, a lower cycloalkyl radical, a lower yn'l)'l"3'dlmethylurea alkoxy radical, or a substituted or unsubstituted g Disclaimer 3,856,503.T0ny Oebalo, Indianapolis, Ind. HERBICIDAL METHOD AND COMPOSITIONS. Patent dated Dec. 24:, 1974. Disclaimer filed Sept. 20, 1976, by the assignee, Air Products and Chemicals, Inc. Hereby enters this disclaimer to claim 3 of said patent.

[Oyficial Gazette N o vember 23, 1976.]

December ELL, 197A d patent H HHH "CH should read should read ---lol-lo5---.

Postemergent A M O P R S T NT OFFICE CERTIFICATE OF CORRECTION should read under column R2,

Dated 5 under column R "166- 168" 5 and under the column Melting Point C, insert -l68- should read UNITED STATES PATE "thiadiazole-E "l,5, l-dimeth l" should read ---l,5-

example 28 of the table should read --H-- -H-; under column R Preemergent H J K L M N O P Q R S T.

Tony Cebalo line ML, -thiadiaZol-2---.

line 10 dimethyl.

t is certified that error appears in the above-identifie end that said Letters Patent are hereby corrected as shown bel Patent No Inventor In column 7,

In column 8, line 61, "1 1/2 1/2" should read ---l-l/2---.

In column 10,

In column 10,

In column ll, example #5 of the table, under the column Melting Point,

In column 15, compounds 28 and +0 should read as follows:

Cpd. Rate,

No. No./A A B c D E F G 7314A Z1 111 2 55 9.57) 225%. h h h A 2732 5 552/ 5 5 122 lh c 1. .1 .55 1. .1 .55 119. .ln h 111 .5. 111 .l45 122 /hw 1.12 .14. 112 .514 111 .2). 122 .5. 111 .u. 111 .5. 111 .1. 19.2 .5. 112 .\n. 112 .2. 111 .l. 111 .2. 111 .25 5

r2050 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent: No. 5 5 Dated December 2%, 197A lr1ventor(s) Tony Cebalo PAGE 2 I2? is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

w "1 i In column 17, compound 55, under the Preemergent column following the rate 0. 5, insert --l l l l l l l l l l l l l l l l l l Under the corresponding Postemergent column, insert 2 i 5 i i 5- In column 19, line 5, "fromm" should read -from-- In column 19, line 52, "applications" should read --application---.

In column 19, line 57, "isophshould read isopho- In column 19, line Q7, "compounds described" should read compounds and compositions described--.

In column 19, line 52, "selectively" should read ---selectivity-.

In column 22, line l5 "yl)l) should read --yl) Signed and Scaled this twenty-second Day of July 1975 [SEAL] Arrest RUTH C. MASON C. MARSHALL DANN Alicsling Officer Commissioner of Parents and Trademarks 

1. A METHOD FOR THE CONTROL OF UNWANTED PLANTS WHICH COMPRISES CONTACTING SUCH PLANTS WITH A PHYTOTOXIC AMOUNT OF A COMPOUND HAVING THE FORMULA
 2. A method as in claim 1 wherein R3 is lower alkyl.
 3. A method as in claim 2 wherein the compound is 1-(5-dimethylsulfamoyl-1,3,4-thiadiazol-2-yl)-1,3,3-trimethylurea.
 4. A method as in claim 2 wherein the compound is 1-(5-dimethylsulfamoyl-1,3,4-thiadiazol-2-yl)-1,3-dimethylurea.
 5. A method as in claim 1 wherein the compound is applied at a rate within the range of from 0.05 to 20 pounds per acre.
 6. A method as in claim 5 wherein the compound is applied at a rate within the range of from 0.5 to 4 pounds per acre.
 7. A herbicidal composition comprising an inert diluent and from 0.25 to 95 percent by weight of at least one compound of the formula
 8. A composition as in claim 7 wherein the compound is one wherein R3 is lower alkyl.
 9. A composition as in claim 8 wherein the compound is 1-(5-dimethylsulfamoyl-1,3,4-thidiazol-2-yl)-1,3,3-trimethylurea.
 10. A composition as in claim 8 wherein the compound is 1-(5-dimethylsulfamoyl-1,3,4-thiadiazol-2-yl)-1)-1,3-dimethylurea. 